Various types of vertical highway barriers exist. One type of barrier, a sound wall, is used for stopping or hindering highway noise from polluting neighboring areas. A sound wall comprises rectangular planar sections, referred to as sound wall panels, which are coupled or adjoined together at posts that are affixed to the ground. Each post includes a groove on each side that faces a sound wall panel. The left side of a panel is slid into the rightward-facing groove of a first post and the right side of the panel is slid into the leftward-facing groove of a second post. In this manner, the panel is held up vertically by the first and second posts. Next, the left side of a second panel is slid into the rightward-facing groove of the second post, and so on and so forth. Thus, each post is coupled to and provides support for two separate panels of a sound wall for a highway. For this reason, each panel must fit snugly between two posts. Therefore, each post must be aligned to within a very small margin of error so as to meet this criterion.
Various factors can hinder the adequate alignment of posts required to accommodate panels between them. Human error and the limitations of surveying equipment may result in the inadequate alignment of a post. Alternatively, certain types of ground or soil can be particularly problematic, such as sand, loose aggregate or ground with a high liquid content, such as swamps, peat bogs and marshes. In such ground conditions problems arise from the inadequate support for the post upon insertion. The use of a pile, which typically comprises a heavy cylindrical object placed in the ground and serving as a support or foundation for the post, can mitigate this problem.
A pile may comprise a metal cylindrical object, such as a pipe, that is driven into the ground with a pile driver of the impact or vibratory type. Alternatively, a grout pile may be poured into a hole drilled into the ground. Such an auger cast pile is installed by rotating a hollow shaft auger (or large screw) into the ground to a specified depth. Grout is then pumped under pressure through the hollow shaft as the auger is slowly withdrawn. The resulting grout column hardens and forms an auger cast pile. A post is then coupled with the pile in some manner, typically by inserting the post into an orifice in the pile or into the pile itself. Alignment of the post within the pile, however, can be difficult.
Due to ground instability, equipment limitations or shifting due to freeze/thaw cycles, the pile may shift, lean or fall off alignment, since it is not anchored in a firm base. In this case, if the post is coupled collinearly with the pile, then the post will be misaligned by the same amount. Further, even if the pile is aligned correctly, the bore within the pile that receives the post may be off-alignment. In this case, when the post is inserted within the bore, then the post will be misaligned by the same amount. Additionally, the width of the bore within the pile that receives the post may be significantly larger than the width of the post, thereby producing a significant amount of play when the post is inserted into the bore. This may further cause the post to be misaligned.
Further, misalignment of one post can propagate to other posts. Because each panel is nearly rectangular, sequential posts must be nearly parallel. For example, if a first post is slightly misaligned toward a panel, then the post supporting the other end of the same panel must be slightly misaligned away from the panel. Thus, a slight misalignment of a first post results in the forced misalignment of a second post.
One approach to the problem of alignment of posts in this situation involves manually checking the post before or during insertion of a panel coupled to that post. Then, using a crane or other heavy equipment, the post is moved into a position of alignment. Often, many attempts must be made until alignment is reached. This approach, however, is cumbersome, labor-intensive and time consuming to execute. Thus, the above approach does not provide an easy and quick means of aligning a post within an already existing pile or foundation so as to accommodate a sound wall panel.
Another approach to the problem of alignment of posts in this situation involves the use of a large template that rests on the ground to support and align the post until the pile grout hardens. The template, however, requires considerable space and is problematic in soft ground. Further, these templates cannot be used in water without temporary support piles.
Therefore, a need exists to overcome the problems with the prior art as discussed above, and particularly for a more efficient way to adequately align a post that is placed within a pile or foundation so as to accommodate a sound wall panel.